1. Field of the Invention
The present invention relates to a carbon heating apparatus utilizing a graphite felt and a manufacturing method thereof. More particularlly, the carbon heating apparatus comprises a carbon heater made of a carbon fiber forming with a predetermined section and length and heat treated in a hydrogen gas atmosphere under a preset high temperature to make uniform surface cut structure, a quartz glass tube for enveloping and sealing the carbon heater, and a pair of termials for securely attaching both ends of the carbon heater to prevent unwanted sparks and looening the carbon heater.
2. Description of the Related Prior Art
Generally, a carbon heating apparatus produces extreme temperatures due to arc discharge and Joule heating through the contact resistance between carbon particles in response to an electric current flowing into both ends of the carbon particles received in an insulator. Since the carbon fiber was invented many years ago, the carbon heating apparatus for producing heat employs carbon yarns, a plurality of twisted carbon yarns or a textile type of graphite felt cut as needed by applying electricity to both ends of the carbon heater. Also, the carbon heating element is enveloped in a glass tube filled with an inert gas, typically using a silica glass or a hard glass. However, the hard glass is not suitable to maintain continuously at extremely high temperatures. Accordingly, a carbon heater for continuously producing high temperatures, such as a semiconductor manufacturing apparatus has a construction that the carbon heater is sealed in the quartz glass to prevent oxidizing in a high temperature environment.
According to FIG. 1 which is illustrating a front view of the conventional carbon heating apparatus, it has a structure that the carbon fiber of the carbon heater (2) is sealed into a bar shaped quartz glass tube (1) and the ends of the quartz glass tube are melted and sealed for stably connecting to the outside power supply lines. In the above illustration, the graphite felt cut to a predetermined length and sectional area is used as the carbon fiber.
As shown in FIG. 2, the upper face of the carbon fiber such as the graphite felt is smoothly formed, while its rough cut of side surface has a lot of minute carbon particles exposed to the outside as shown in FIG. 3. The exposed particles are easily separated by the outside light impact. In the case of using the carbon heating apparatus for heating or cooking, despite precisely controlling and cutting the sectional area and length to derive a required resistance and a resulting power consumption, many users would typically cut the graphite felt to a desired size and shape as needed by using tools such as a knife or scissors, etc.
At this time, the minute carbon particles or the unwoven pieces produced from the graphite felt cut arc exposed at the cutting surface. If it is sealed into the quartz glass tube without treatment, the exposed carbon particles are melted inside of the quartz glass tube to produce unwanted arcs and interrupt the operating cycle when the quartz glass tube is heated. Thereby, it will be negatively impacting the thermal efficiency and durability of a lamp and the life of a machine.
On the other hand, both ends of the carbon fiber processed as above use materials such as molybdenum or nickel to make a terminal as a general method, it is processed to have the shape of a spring.
In this case, it generates several problems due to contraction strength or compression strength. In the case of connecting both ends of the carbon fiber using the spring shape of terminals, arc discharge maybe produced between the terminal and the carbon fiber materials causing contraction and expansion relative to each other, thereby causing a short therebetween or separation of the fiber itself from the terminal, increasing contact resistance therebetween and having a negative impact on durability.